The present invention relates to an optical data recording device using SIL (Solid Immersion Lens) in order to store information with high capacity, and more particularly to the multiple optical-recording apparatus capable of storing multiple information and playing by forming multiple focus within the SIL.
The present invention relates to multiple optical-recording apparatus, which speeds up multiple information recording speed and transfer rate by forming multiple focus in the optical information storage device adopting near-field recording technology using SIL (Solid Immersion Lens) in order to overcome the diffraction limit of light.
The device storing information by focusing laser beam on a spot of the recording medium which is having the characteristics of magneto-optic or phase shift have been developed toward decreasing access time and increasing transfer rate and information recording density.
Although the size of the optical spot which is focused on the recording medium should be decreased, due to the diffraction limit of the light it can not be decreased below the constant size in the given wavelength.
There are DVD (Digital Versatile Disk) and near-filed recording technologies for increasing storage density and overcoming the limit.
The DVD technology is what changing the focal length of the focusing light in order to make several layers"" mediums to be formed in the recording medium and the focusing light to be focused on each layer. However the DVD technology could not increase the recording density fundamentally, and also the transfer rate was not improved so obviously.
Meanwhile, in the near-field optical recording technology largely there are aperture and SIL technologies.
The aperture technology is that the optical energy distribution in the aperture is transferred to the recording medium without the influence of the diffraction as large as the size of the aperture by penetrating the light into the aperture after approaching the distance between the aperture and the recording medium to below several tens of nano-meter. While the optical fiber is used as the aperture and the light is transferred by making aperture of below several tens of nano-meter in the sharp end of the optical fiber which is coated with metal film of the optical fiber.
However, this technology has a disadvantage that the optical intensity passing through the aperture is too little to obtain the optical energy needed for real recording.
The SIL technology utilizes the principle that when the light is focused into the medium with high refractive index the wavelength is decreased and the refraction angle is increased and then the light is focused within the hemispherical SIL medium and the size of the focusing spot is decreased below the diffraction limit.
By utilizing the principle, the SIL technology makes the flat bottom plane of the SIL to be nearly approached to the recording medium and is implemented the light to be focused into the plane within the SIL medium. Herein, due to the high refractive index of the SIL medium, the focusing light forms the spot which is below the diffraction limit by the short wavelength and high numerical aperture. And the information is recorded through the transfer on the recording medium which is nearly approached without the influence of the energy diffraction of the spot.
By utilizing these methods, in order to do faster access and transfer, the technology mounting on the flying head which is adopted in the existing hard disk has been proposed and researched.
However, while the access time was considerably increased, there is limit in speeding up the recording speed and transfer rate. The reason is that as the flying head technology is the mechanical transfer and access fundamentally, there is the limit caused by the mechanical movement.
It is preferable that a multiple optical-recording apparatus, which is speeding up the recording speed and transfer rate by forming the multiple focus, comprise an optical source means consisting of two or more diverging points, an optical detecting means consisting of optical detecting devices for detecting two or more converging lights, an optical means for recording the information into the optical recording medium and reading out by forming two or more focuses, an optical beam splitting means for splitting the light converging into said optical detecting means and the light diverging from said optical source means, and an optical inducing means for inducing the light to said optical means from said optical source means and then for inducing the light to said optical detecting means from said optical means.
It is preferable that the multiple optical-recording apparatus is set up in the exterior and forms two or more diverging points in the interior of said optical means after inducing the light from the optical source.
It is preferable that the optical source means is composed of two or more semiconductor optical sources in which one light is diverged from one chip.
It is preferable that the optical inducing means for inducing light to the interior of said optical means from said optical source means is an optical fiber.
It is preferable that the optical inducing means for inducing light to the interior of said optical means from said optical source means is an optical waveguide.
It is preferable the optical means is set up in the interior of said optical means and is equipped with the optical source which is composed of two or more diverging lights and then forms two or more diverging points.
It is preferable that the optical detecting means is set up in the interior of said optical means.
It is preferable that the optical means comprise a reflection mirror for reflecting the points diverged from said optical source means, one or more refractive optical device for controlling the distance ratio between the points knotting focuses and the distance between the reflected points from said reflection mirror, and a refractive optical device which is composed of curved plane and flat plane making two or more focuses to be knotted.
It is preferable that the refractive optical device is the refractive optical device composed of curved plane or flat plane.
It is preferable that the optical means comprise one or more refractive optical device making the diverging points to the collimated light as the refractive optical device controlling the distance ratio and one or more refractive optical device focusing the collimated light.
It is preferable that the optical means makes two or more focuses to be knotted in the plane of the refractive optical device which is composed of curved plane and flat plane.